Objectives: We investigated the changes in rat dentate gyrus volume in a penicillin-induced epilepsy model. Study Design: The study included 12 adult female Sprague-Dawley rats (220-350 gr) of 16 to 20 weeks. The animals were aşigned to receive either intracortical saline solution or penicillin G (500 IU). A week later, the brains were removed and frozen in a cryostat. All tişues were sectioned at 150 µm and stained with hematoxylen and eosin. The sections were visualized under light microscope and cell layer images of the dentate gyrus granulare were transferred to a monitor. The volumes were quantified stereologically using the Cavalieri 's principle. Results: The mean dentate gyrus volume of penicillin administered rats was greater than that of the control rats. However, this increase was not statistically significant (Mann-Whitney U-test, p>0.05). Conclusion: The effects of experimental epileptic seizure models on different areas of the brain may be more objectively evaluated both by the number of neurons and quantification of volume changes.